<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    table,
    tr,
    th,
    td {
      border: 1px solid #ccc;
    }

    tr {
      height: 40px;
    }

    table {
      border-collapse: collapse;
      width: 630px;
      text-align: center;
      margin: 20px auto;
    }

    thead {
      background-color: yellowgreen;
    }

    fieldset {
      width: 600px;
      margin: 0 auto;
    }

    input {
      height: 20px;
    }
  </style>
</head>

<body>
  <div id="app">
    <fieldset>
      <legend>学生录入系统</legend>
      <p><span>姓名：</span><input type="text" name="username" class="username"></p>
      <p><span>年龄：</span><input type="text" name="age" class="age"></p>
      <p><span>性别：</span><select name="sex" id="sex">
          <option value="男">男</option>
          <option value="女">女</option>
        </select></p>
      <p><span>手机：</span><input type="text" name="phone" class="phone"></p>
      <p><button id="but">确认提交</button></p>
    </fieldset>
    <table>
      <thead>
        <tr>
          <th>姓名</th>
          <th>年龄</th>
          <th>性别</th>
          <th>手机</th>
          <th>删除</th>
        </tr>
      </thead>
      <tbody class="tbody"></tbody>
    </table>
  </div>
</body>

</html>